Access control system for restricted area

ABSTRACT

An access control system for controlling the entry and exit of personnel through a door or a gate of a restricted area. A person seeking to enter the restricted area inserts a personnel identification card with magnetically encoded data thereon into a card reader located outside the restricted area. Then, a secret number is entered on a keyboard. The system performs checks on the card and keyboard data to determine if the person seeking to enter the restricted area is authorized to enter this area. If all the checks are passed satisfactorily, the door is opened and the person can enter the restricted area. A written record of each attempt to enter the restricted area is made by a printer thereby providing a chronological record of all system events. The system also provides means for preventing persons in a defined group from entering a restricted area as well as circuitry to prevent entry by selected individuals. The system also includes a card erase mechanism which erases the magnetically recorded card data after a predetermined number of unsuccessful entry attempts. Since only the magnetically encoded data is erased, the card may be used by this person for other purposes as printed and photographic information is usually included on such cards. The access control system also includes egress monitoring in the form of a printed record of personnel egress from the restricted area, the egress monitoring becoming active when the individual leaves the restricted area and allows the door to close behind him.

Moorman et al.

[ ACCESS CONTROL SYSTEM FOR RESTRICTED AREA Inventors: Charles J. Moorman; Frederick A.

Reuter, both of Cincinnati, Ohio; Daniel F. Yorke, Brookfield Center, Conn.; Martin R. Meyer, Cincinnati, Ohio The Mosler Safe Company, Hamilton, Ohio 22 Filed: Oct. 2, 1973 211 App]. No.: 402,703

[73] Assignee:

Primary ExaminerHarold I. Pitts Attorney, Agent, or Firm-Wood, Herron & Evans [57] ABSTRACT An access control system for controlling the entry and DOOR J2 e l 5. K5 PEHSONNH DOOR I SLNSOR LOCK sev ii ul [451 Feb. 11, 1975 cire'cks'oii the card aiid k e yboard data to determine if the person seeking to enter the restricted area is authorized to enteNhis area. If all the checks are passed satisfactorily, the door is opened and the person can enter the'restricted area. A written record of each attempt to enter the restricted area is made by a printer thereby providing a chronological record of all system events. The system also provides means for preventing persons in a defined group from entering a restricted area as well as circuitry to prevent entry by selected individuals. The system also includes a card erase mechanism which erases the magnetically recorded card data after a predetermined number of unsuccessful entry attempts. Since only the magnetically encoded data is erased, the card may be used by this person for other purposes as printed and photographic information is usually included on such cards. The access control system also includes egress monitoring in the form of a printed record of personnel egress from the restricted area, the egress monitoring becoming active when the individual leaves the restricted area and allows the door to close behind him.

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SHEET P. 0F 3 /l N ///j w /09 w; /02 //f .4 CLOCK AND COUNTER DECODERQ n+l /fl/ L I w START fig ss TIMER I El 5885 RESPONSE/ E OR EE'XE 1@E@"' A M 4 W R 59,25

ENTRY l *AND READ CARD READY 2R4 I AT DOOR 2 DOOR2 5 EGRESS 5565 5555 (MN O DECODE DECODE BLOCK ENTRY READ CARD E Hi m AT DOOR s IHIOOOOXXXX IIIIOOOIXXXX llll llll XXXX I 3,866,173 SHEET 3 BF 3 N$WN EE 50 i1 PATENTED F551 1 5 ACCESS CONTROL SYSTEM FOR RESTRICTED AREA BACKGROUND OF THE INVENTION This invention relates generally to the field of access control system for assuring that only authorized personnel are permitted to enter or leave restricted areas and particularly to systems including expensive egress control, group blocking, erasure but not destruction of cards after a predetermined number of unsuccessful entry attempts and also a system which includes area access authorization information which is coded in machine readable form on the individuals personnel identification card.

Access control systems have been proposed heretofore which utilize personnel identification cards to control movement of personnel through doorways. One typical system has utilized personnel identification cards in connection with a verification check to determine whether the person possessing the card is a person who has been authorized to use the card. The verification check typically requires the person possessing the personnel identification card to insert the card into a card reader which then reads the machine readable data encoded thereon and stores this data at a central control location. The person seeking entry is also required to enter a secret identification number on a keyboard located near the card reader. This secret identification number is then utilized by a verification circuit to determine whether the person possessing the card also knows the proper secret identification number which corresponds to that card. If the secret number is correct, the system assumes that the person possessing the card is authorized to enter.

In other prior art systems, checks other than verification checks have been proposed. One such check has been to determine whether a persons authorization to enter a restricted area has been withdrawn. Typically such proposals include a computerlike central processing unit which compares the personnel identification number read from the card against a list of identification numbers with respect to which authorization has been withdrawn. Should a comparison be found between the number read from the card and one of the numbers on the list of unauthorized personnel, the apparatus responds to prevent opening the door to the restricted area despite the fact that other checks performed by the access control system such as proper verification, were satisfactory.

A failing of such proposed prior art systems, however, has been the inordinate cost of blocking feature for preventing entry of unauthorized card holding personnel. This problem has been particularly acute where large groups of card holders are to be blocked. For example, if a strike of union workers is in process and management desires to prevent all union members from entering the plant during the strike, separate entries would have to be provided in the list of unauthorized personnel to correspond to each union employee whose entry is to be denied. As such, prior art systems have proved to be extremely unwieldy in providing blocking of personnel on a group basis, that is, denying access to restricted areas to groups of employees rather than individual employees.

Some of the proposed prior art access control systems have extended their surveillance to include egress monitoring as well as entry monitoring. Such prior art proposals typically include a card reader and, in some cases, a keyboard located at each entrance to, as well as at each exit from, restricted areas. In some such systems, in order to leave a restricted area, the individual must insert his personnel identification card into the card reader and also enter his secret identification number in the same identical manner as required to enter the restricted area. In other systems, the person seeking to leave the restricted area need only enter his personnel identification card into the card reader. In both such approaches, however, the system requires that a card reader be located on both sides of the doorway to the restricted area. As such, the cost of each door installation is greatly increased because at least two card readers are necessary at each doorway. Furthermore, for the systems having a keyboard on both sides of the restricted area doorway, the cost is even higher because two keyboards as well as two card readers are required at each doorway.

A further typical capability of proposed prior art access control systems has been to permit personnel access to different restricted areas according to individualized access authorization information maintained at the central location which is addressed with the individuals identification number read from the card. Consequently, when a person seeks entry to a restricted area, his personnel identification number must be read from his identification card and the acces authorization information for this individual retrieved from the central storage. After the access authorization information is retrieved, it must then be checked to determine whether the individual is seeking to enter a restricted area to which access has been authorized. Consequently, access authorization checks in such prior art systems require relatively complicated computer technology and large scale storage capability. In fact a computer itself is necessary to perform the access authorization checking functions. Consequently, such systems have proved to be complicated in design and very expensive to install.

In view of the foregoing difficulties with the prior art, it is the primary objective of this invention to provide an access control system with multiple checks which is less expensive than prior access control system.

It is a further objective of this invention to provide an access control system which controls entry to restricted areas, exit from restricted areas, and fully documents all events occurring at the doorways to such restricted areas with a minimum of card reader/keyboard hardware.

It is a still further objective of this invention to provide an access control system which permits rapid and inexpensive blocking of access to restricted areas for all individuals in selected groups of personnel.

In order to achieve these and other objectives of this invention, an access control system is provided which includes, at each lockable door to a restricted area, a door control unit having a door lock, as well as a single keyboard and a single card reader both of which are located outside of the restricted area. Each keyboard, card reader and door lock is connected via a communication link to a central control which is operative to control much of the operation of all elements of the door control unit. When an employee wishes to enter a restricted area, he inserts his personnel identification card into the card reader and also enters a secret identification number on a keyboard. The central control responds to the keyboard data and the card data to determine whether the door lock should be released. In so doing the central control performs a verification check to determine whether the person possessing the card is authorized to use the card. In addition, the central control determines whether the card in the reader corresponds to a card issued for the particular system or plant. Additionally, the central control checks the access data on the card to determine whether the individual has been authorized to enter the specific restricted area or gate through which entry is sought. Assuming that all of the different status checks are passed satisfactorily, the door lock is released and the individual permitted to enter the restricted area, whereupon a printer is actuated to record the identification number, time, door and the fact that an entry has occurred.

The system does not include a second card reader nor keyboard located inside the restricted area for controlling egress. The system does, however, include a floormat sensor inside the door which detects personnel approaching the door from inside of the restricted area. The sensor activates a buzzer or other humanly perceptible signal means located outside the restricted area to remind the person after leaving the restricted area to insert his personnel identification card into the card reader located outside the restricted area. When the restricted area door has closed and the card inserted into the reader, the buzzer stops and the central control reads the card data and actuates the printer to record the identification number, time door and the fact that the person so identified has left the restricted area.

The system includes two blocking features, that is,

the system can selectively block personnel from entering restricted areas. One blocking feature permits selective identification of individuals who possess a proper personnel identification card but who are no longer authorized to enter the restricted area. The second feature permits selective identification of groups of individuals possessing proper personnel identification cards who all are not currently authorized to enter the restricted area. The selective identification of blocked individuals is achieved by a decoding circuit and a matrix board arrangement. Diode pins are inserted in locations on the matrix board which correspond to blocked individuals. Ifa block signal passes through the decoder and also through the matrix board, the signal indicates the individual is not authorized to enter the restricted area. The group blocking is accomplished simply by decoding some but not all of the personnel identification number digits. Combinations of these digits can be selected by a switch arrangement so that a block signal will be generated for all individuals having the selected personnel identification number digits in common.

In all instances, the access control system of the present invention provides a printed record for each detected system event. This record is generated by a recorder which, in the preferred embodiment, is a printer provided to produce the record of the type of event which has occurred, the personnel identification number from the card read by the card reader at the time the event occurred, the door at which the event occurred, the date, and time.

The foregoing and other objects, advantages and features of this invention will become more clear from the following detailed description of one preferred embodiment of the invention taken in connection with the drawings which form a part of the original disclosure.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic system diagram showing the central control, the switch and the door control unit.

FIG. 2 is a schematic diagram of the Sequence Controller shown in FIG. 1.

FIG. 3 is a schematic diagram showing the Status Check circuitry in greater detail.

FIG. 4 is a schematic diagram showing a portion of the blocking circuitry.

DETAILED DESCRIPTION Referring now to FIG. 1, the access control system thereshown includes a door control 1, a switch 2, and a central control 3. In its preferred form, the system includes more than one door control, however, FIG. 1 shows only one such door control in order to keep the drawing relatively simple. Each door control 1 controls a single door to a restricted area controlled by the overall access control system. The'switch 2 interfaces with all of the door control units 1 of the system and provides a means for connecting only one door control unit at a time to the central control 3. The central control 3 is operative in response to signals from a door control 1 to activate the system according to a predetermined sequence which depends on the specific event occurring at the door.

Each door control 1 includes a card reader 10 and a keyboard 12 which are physically located outside the restricted area but closely adjacent the controlled door. The card reader 10 comprises, in the preferred'embodiment, a magnetic card reader for reading magnetically encoded information on a magnetic stripe located on a typical personnel identification card. Such cards are commonly found in automatic cash dispensing machines, other access control systems as well as some credit card verification systems. The keyboard 12, for the preferred embodiment, comprises a typical data entry keyboard including eight numbered keys. These keys, when depressed by personnel seeking entry, produce a coded electrical signal which is preferably stored in a register located at the keyboard itself. While the preferred keyboard 12 has seven different keys, it will be readily recognized by those of skill in the art that keyboards having more or less keys than those for the preferred keyboard 12 may also be advantageously utilized in connection with an access control system of the type herein described.

Typically, a door control 1 having a card reader 10 and a keyboard 12 is utilized in the following manner to control the entrance of personnel into a restricted area. Upon approaching a restricted area controlled by the access control system, an employee or other authorized person inserts a personnel identification card previously provided to the individual into the card reader 10. In the preferred form, each card has a magnetic stripe encoded with a multi-digit machine readable number. The card may also have a photograph and other data in printed form to assist in personnel identification. After inserting the card into the card reader 10, the individual enters into the keyboard 12 a secret identification number known only to the authorized card holder. A digit counter 14 is responsive to the keyboard 12 to count the number of digits entered on the keyboard 12. In the preferred embodiment, when four digits have been entered and stored at the keyboard 12, the digit counter 14 provides an output signal which is transmitted over a communication link, or a connecting wire 16, to the switch 2. The signal on this connecting wire 16 is an entry ready signal which indicates to the switch 2 that all actions at the door control 1 required of a person seeking to enter the restricted area have been completed and no further action can be taken at the door control 1 until the central control 3 performs the status checks to be described in greater detail later.

The switch 2 is operative to scan the signals on the various connecting wires which link the switch 2 to the system door control units 1. The switch 2 determines the priority of these door control units 1 and then connects only one such door control unit 1 to the central control 3 at any given time. Assuming, that no other door control unit 1 has an active signal on a connecting wire 16, the entry ready signal on the connecting wire 16 will be transmitted by the switch 2 to the central control 3. The switch 2 is also operative to connect all the communications lines, to be described later, between the door control 1 of the door given priority by the switch 2 to the central control 3.

At the central control 3 the entry ready signal which appears on the connecting wire 16 will be operative to activate a Sequence Controller 18. The Sequence Controller 18, which will be described in greater detail below in connection with FIG. 3, is operative to produce a sequence of timing signals to control the operations at the central control 3. In response to the entry ready signal, the Sequence Controller 18 at the central control 3 will cause the stored keyboard data and the data from the card to be transmitted to a data storage element 20 at the central control. The data storage element 20 preferrably comprises a data storage register for storing electrical representation of the keyboard data and the card data. The actual sequence of these two operations is not critical, however, the Sequence Controller 18 will be operative to produce a Read Card at Door 1 signal which is transmitted from the central control 3 through the switch 2 and over the communications wire 22 to the card reader to cause the card reader to read the personnel identification information which is recorded in machine readable form on the personnel identification card inserted into the card reader. As indicated earlier, for the preferred embodiment of this invention, the personnel identification card comprises a card much like those used for automatic cash dispensing apparatus which includes a magnetic stripe on which personnel identification information is magnetically recorded. As such, the card reader 10 is preferably a magnetic card reader. The data read in response to the read signal on the wire 22 is transmitted over the data communication wires 24 to the switch 2 and then to the data storage 20. The card data thus read is stored in a register in the data storage so that the central control can use this data to perform status checks. The storage of the card data in the data storage 20 is operative to produce a Response Signal which is used by the Sequence Controller 18 in a manner to be described later to cause another control signal to be developed.

Such a further control signal developed by the Sequence Controller 18 is operative to generate a keyboard read signal on line 26 to read the keyboard data stored at the keyboard 12. This keyboard read signal is transmitted from the Sequence Controller 18 through the switch 2, and over the communication wire 26 to the keyboard 12. in response to the signal on the wire 26, the keyboard 12 is operative to transmit the keyboard entered data over the data communication wires 24 through the switch 2 to the data sotrage 20. Receipt of the keyboard data at the data storage 20 is also operative to generate a Response Signal which is sent to the Sequence Controller 18 to cause the Sequence Controller 18 to actuate another control signal line in a manner to be described later.

A door lock 28, which is normally in its locked position, is located at each controlled door. The door lcok 28 is operative to prevent opening of the controlled door from outside the restricted area unless the door lock 28 receives a door unlock signal on the wire 29. The door can be manually opened from inside the restricted area. When this door unlock signal is present on the wire 29, then the controlled door can be opened from the outside and persons can pass freely therethrough for a predetermined period of time.

The central control 3 is generally operative when a person is seeking to enter a restricted area in the following manner. After the Sequence Controller 18 has read the keyboard data and the card data into the data storage 20, this data is utilized by the central control 3 to determine whether the door lock 28 will be opened to permit the individual to enter the restricted area. In order to determine whether such entry will be permitted, the central control 3 must perform a number of checks on the data received from the keyboard 12 and the card reader 10. The keyboard data, as indicated above comprises four digits which correspond to a secret number. The card data stored in the data storage 20, on the other hand, comprises a personnel identification number, a system number, access area information and any other data which may be utilized by the access control system, or, indeed, other related systems. The personnel identification number included in the card data is a multi-bit number which is assigned to the individual possessing the personnel identification card. For the preferred embodiment, the personnel identification number comprises twelve binary bits of data which correspond uniquely to the individual possessing the card. The system number included in the card data comprises several data bits of information which uniquely identify the access control system on which the card data for the personnel identification card in the card reader was generated. The access area data from the card comprises a number of data bits which, in the preferred embodiment, is twelve bits for identifying the areas which the individual is permitted to enter or leave. As will be indicated later, the twelve bits of access area data are divided in half so that two different sets of access area information bits are formed for use by the system with one set of bits being used during daylight hours and the second set of bits being used during the night.

The central control 3 performs a verification check to determine whether the individual who has entered a secret number on the keyboard 12 has actually entered the proper secret number which corresponds to the card data read by the card reader 10. This verification is performed by the verification circuit 30. This verification circuit 30 is described in greater detail in the copending patent application entitled Access Control Apparatus, Ser. No. 293,595 which was filed on Sept.

29, 1972, and is herein incorporated by reference. While one specific preferred embodiment is described in that copending patent application, it will be recognized by those of skill in the art that numerous other verification systems might be utilized in place of the specific verification circuit 30 described in the above identified copending application.

The function of the verification circuit 30 is to provide a signal on its output wire 32 which indicates that the proper secret number was entered on the keyboard 12 for the specific personnel identification card which was read by the card reader 10. This favorable comparison indicated by the verification circuit 30 is but one of the status checks considered by the status check circuitry 34. The status check circuitry 34 also determines in a manner described in greater detail later whether the system number from the card data read by the card reader corresponds to the system number of the access control system which read the card. A proper comparison of these two numbers is necessary to permit the individual who has attempted to enter a restricted area to actually enter this area. Furthermore, the status check circuitry 34 is operative in a manner described later in greater detail to determine whether the access area data on the personnel identification card read by the card reader 10 indicates whether the individual possessing the card is authorized to enter the restricted area at the particular time entry is sought.

The status check circuitry 34 also makes a determination in a manner described in greater detail below of whether the individual is blocked from entering the restricted area. Assuming that all of the above identified checks have been passed successfully, this information is transmitted from the status check 34 to the Sequence Control 18 which then responds to activate the printer 36 as well as to send a signal to unlock the door. The unlocked door signal is transmitted from the Sequence Controller 18 through the switch 2 and over the connecting wire 38 which turns on a single shot timer circuit 40 located at the door control 1. The single shot timer circuit 40 produces an output signal, which, in the preferred embodiment, lasts for approximately 20 seconds although the time can be adjusted to suit user requirements. This output signal is connected to the wire 29 which comprises, as indicated above, the door unlock signal operative to unlock the door lock 28 and permit the individual to open the door controlled by the lock 28 and pass through the doorway into the restricted area. While the door lock 28 is unlocked, the Sequence Controller 18 is also operative to activate a recorder 36 which in the preferred embodiment is a printer. Other types of recorders might be provided to suituser requirements, however, it is desirable to provide a recorder which will produce a written record of each system event. In the preferred embodiment, the recorder 36 is operative to print an event code which corresponds to the type of event which has occured at the door control 1. The recorder 36 also prints a number corresponding to the personnel identification number read from the card by the card reader 10. An indication of the door at which the event occurred is also printed. The recorder 36 also prints the date and the time at which the event occurred. As such, the printer provides a complete written record of the time, date and the door at which a given identified individual attempted to enter a restricted area as well as an indication as to whether that attempt was successful or not.

As will become more clear later, the event identification indicates whether the identified individual was entering or leaving the restricted area as well as to indicate, according to a predetermined priority, whether any status checks were not passed successfully which thereby prevented entry to the restricted area.

The above description relates to system operation for successful entry attempts. The system in FIG. 1, however, responds in a somewhat different manner if all of the status checks are not satisfied. Specifically, the Sequence Controller 18 does not generate the door unlocked signal unless all the checks are successfully passed. Therefore, an individual is not permitted to pass through the doorway unless all checks are successfully passed. if an unsuccessful entry attempt occurs, the individual may then respond in one of two manners. He may proceed to a different entrance to the restricted area where a guard or some other person is stationed who can determine from written information on the card whether the individual should be allowed to enter the restricted area. On the other hand, the individual may again attempt to enter the restricted area by placing his personnel identification card in the card reader 10 and again enter his secret number on the keyboard 12. Each such entry of keyboard data is operative to actuate the central control 3 in the manner described above. Each keyboard read signal on wire 26 is operative in the manner described above and also operative to increment an entry attempt counter 41 which counts the number of attempted entries at the door which occur prior to the generation of a door unlock signal on the wire 29. If the entry attempt counter 41 should ever reach a predetermined selectable value, this indication is applied to the wire 42 which is connected to the card reader 10. Upon receipt of a subsequent card read signal on wire 22 while the indication is present on wire 42, the card reader 10 responds to this condition by erasing the magnetically encoded data on the personnel identification card. However, the card is returned to the person seeking entry to the restricted area. This permits the individual to use the card for other purposes such as obtaining entry through an attended entrance point but would prevent further access through unattended automatically controlled doors.

The entry attempt counter 41, as indicated above, is incremented each time an attempted entry occurs. The entry attempt counter is incremented by the read keyboard signal transmitted over the wire 26 from the switch 2 to the door control 1 indicating that keyboard entered data should be read to the central control 3. Since the keyboard data is only read on entry attempts, the entry attempt counter 41 is incremented only when an attempted entry occurs. The entry attempt counter 41, on the other hand, is reset to a value of zero whenever the door lock 28 is unlocked thereby indicating that the proper status checks have occurred in order to permit an individual to enter the restricted area.

The access control system shown generally in FIG. 1 is also operative to provide a written record of all persons leaving the restricted area. The system is operative in the following manner to provide this record. At each doorway, a personnel sensor, such as a floormat 46, is provided. This personnel sensor is generally located just inside the door to the restricted area so that an individual approaching the door from the inside will be detected thereby, such as by stepping on the floormat 46. The personnel sensor provides an electrical signal on the wire 48 which sets a flip-flop 50. The personnel sensor 46 also starts a 20 second single shot timer 51 whose output is inverted by an inverter 53 to produce a logical zero signal at the inverter 53 output. When the door is opened by the individual leaving the restricted area, a door switch 52 produces a door open signal on the wire 54 indicating that the door is open. This signal is applied to one of the inputs to an AND gate 56. The other AND gate 56 input is connected to the output of flip-flop 50. When the door switch 52 produces a door open signal on wire 54 and when flip-flop 50 is set, the input conditions to the AND gate 56 are at the proper level to produce an output signal on the wire 58. When this signal occurs on the wire 58, a second flip-flop 60 becomes set. The setting of this flip-flop 60 will provide an egress signal on the output connecting wire 62 which extends between the door control 1 and the switch 2 to indicate to the switch that an egress has occurred at door 1. This egress signal is used by the Sequence Controller 18 in a manner to be described later.

The system provides a positive control of personnel when individuals leave restricted areas. All personnelare instructed to present their personnel identification card to the card reader when they leave the restricted area. The card reader 10 may be located some distance from the controlled door so that the door cannot be held open by the person leaving the restricted area in an attempt to defeat the system. In the preferred system, however, the system cannot be so easily defeated because the card reader 10 is actuated to read a card only after the door has closed behind the person leaving the restricted area. This control is accomplished electronically in the following manner.

When a person opens the restricted area door, the flip-flop 60 produces an egress signal at its output. This egress signal is at the binary one state and is applied to one input of an AND gate 61. A second input to the AND gate 61 is at the binary one state when a personnel identification card is detected in the card reader 10. The reader 10 includes a card detector, not shown, for detecting cards inserted in the reader 10. The card detector may comprise a switch whose binary output is changed by the presence of a card in the cardreader 10. When a card is not present in the reader 10, the card detector output signal on wire 59 is a binary one. An inverter 63 is connected in series between the wire 59 and the second input to the AND gate 61. Consequently, when the card detector detects a personnel identification card in the card reader 10, the second input to the AND gate 61 will be at the binary one state. The third input to the AND gate 61 is at the binary one state when the door is closed as indicated by a binary zero signal on wire 54. An inverter circuit 65 is connected between the wire 54 and the third input to the AND gate 61 to produce a binary one at the third input to AND gate 61 when the door is closed. When all three inputs to the AND gate 61 are at their binary one state, the output thereof has a binary one" state which is passed through the connected OR gate 67 which produces at its output a START signal. This START signal is connected to the switch 2 and then to the Sequence Controller 18 by the switch 2. The Sequence Controller 18 responds to this START signal in a manner to be described in greater detail later. Briefly, however, the Sequence Controller 18 responds to the START signal to start a predetermined sequence of events to control the system. When a normal egress occurs, that is when a person leaves the restricted area, allows the door to close and presents his personnel identification card to the card reader 10, the system will read the card and then make a record of the event by actuating the recorder 36 to produce record of the event which includes the date, time, door number, personnel identification number and the event code identifying that an egress occurred. This system operation will be described in greater detail later.

When a person leaves the restricted area as described above, the personnel sensor 46 detects the person approaching the door from inside the restricted area. When the door switch 52 detects that the door is open, flip-flop will become set. The output of flip-flop 60 is connected to one input of an AND gate 68. The second input to the AND gate 68 is connected to the output of an inverter circuit 53. The AND gate 68 will produce a binary one signal when the input conditions are both at the binary one state. When the flip-flop 60 is set, indicating an egress has occurred at the door and when the output of the inverter 53 is a one, which occurs after the single shot timer 51 times out (i.e. after a 20 second period), a binary one signal appears at the output of the AND gate 68 which passes through the OR gate 67 and produces a START signal. The Sequence Controller 18 will be started when the switch 2 connects the door control 1 to the Central Control 3 and the system will record that an egress occurred, however, no personnel identification number will be printed because no card was presented to the card reader 10 by the person leaving the restricted area before the single shot timer 51 timed out.

In order to remind personnel leaving a restricted area that they should insert their personnel identification card into the card reader 10 after leaving the restricted area, a humanly perceptible reminder signal is generated at a location near the card reader 10 when an egress is detected. The humanly perceptible signal is generated in response to two different conditions at the door control 1. The first condition occurs when the flip-flop 60 becomes set which indicates the personnel sensor 46 has detected an individual approaching the door from the inside of the restricted area and the door has been opened. The binary one at the output of the flip-flop 60 is electrically connected to one input of an AND gate 64. The second input to the AND gate 64 is electrically connected to the wire 59 which, as indicated earlier, has a binary one signal thereon whenever no personnel identification card has been inserted into the card reader 10. When both of the inputs to the AND gate 64 are at their binary one state, the output thereof is operative to actuate a humanly perceptible signal means 66 which is operative to produce either a visual or audible signal to remind the individual leaving the restricted area to insert his personnel identification card into the card reader 10. The humanly perceptible signal means 66 is preferably in the form of a buzzer which produces an audible sound although va flashing light or other visual reminder could be employed.

The humanly perceptible signal generated by the signal means 66 will remain active until one of two events occur. One such event is the insertion of a personnel identification card into the card reader 10 which causes the signal on the wire 59 to change to its binary zero" state indicating that a card has been inserted into the card reader 10. When this condition occurs the AND gate 64 is no longer operative to actuate the signal means 66. The second condition which turns off the signal means 66 occurs when the flip-flop 60 is reset as this condition will cause a binary zero" signal on wire 62 which is also operative to turn off the signal means 66. This latter condition is produced, as will be indicated in greater detail later, by the receipt at the door control 1 of a read card signal on the wire 22 which is operative to reset the flip-flop 60. Consequently, a humanly perceptible signal at the card reader is generated by the signal means 66 after an egress is detected at the door control 1 and this signal will remain activated until either the individual inserts his personnel identification card into the card reader 10 or a signal is received at the door control 1 to actuate the card reader 10.

Whenever an egress has occurred at the door to the restricted area as indicated above, the Sequence Controller 18 will cause the card reader 10 at the door control l to read a personnel identification card whether one has been inserted into the card reader 10 or not. The read card signal is generated by the Sequence Controller 18 in a manner described later and transmitted from the Central Control 3 via the switch 2 to the wire 22 at the door control 1. The read card signal on wire 22 has a number of functions. In the first place, it is operative to reset flip-flop 60 and also flip-flop 50. Additionally, the read card signal is operative to activate the card reader 10 and cause it to read any card inserted therein.

On a normal egress, the card reader 10 will read a personnel identification card and the data read therefrom will be transmitted over the wire 24 through the switch 2 to the Central Control 3 and stored in the data storage 20. Once this occurs, the Sequence Controller 18 will actuate the recorder 36 to permanently record that an egress occurred, the personnel identification number of the person who left the restricted area, the door number, the time and the date. If, on the other hand, no card was read by the card reader 10, even though an egress was detected at the door control 1, the Sequence Controller 18 will also actuate the recorder 36. In this situation, however, an egress will be indicated, but no personnel identification number will be printed because there is no way of knowing, without reading a card, the identity of the individual who left the restricted area.

The access control system of the present invention may, in addition to the above type of checks, include a separate alarm system for monitoring various alarm conditions throughout the system. For example, a separate alarm may be provided to indicate that a door is open at a time when the door should be closed and locked. This separate alarm condition is provided at the output wire 72 of an AND gate 70. The signal on wire 72 may be operative to actuate a bell, buzzer, light or any other alarm either at the door itself or at some remote location. This alarm condition is generated when three separate conditions occur simultaneously at the input to the AND gate 70. Firstly, the door switch 52 must provide a door open signal on the wire 54 indicating that the door is open. A second signal is provided from the output of an OR circuit 75 whose inputs are inactive only when the output of the single shot timer 40 or 51 is active, i.e. during times when the door is permitted to be open. As such, the output of the OR circuit 75 will provide a blocking signal to the input of the AND gate 70 whenever the door is permitted to be open. The third input to the AND gate is on the activate separate alarm wire 78 which has a signal having a binary.one level when the separate alarm system is actuated. Consequently, when the door switch 52 indicates that the door is open, the single shot timer 40 and 51 not running and the separate alarm circuit is activated as indicated by a signal on wire 78, each input to the AND gate 70 will be at its binary one level and the AND gate 70 will produce a separate alarm signal on wire 72 that indicates the door is open at a time when it should not be open. This separate alarm signal 'will actuate a remotely located alarm in response to which security personnel can take appropriate action.

In some instances, and especially when a large number of people are either entering or leaving the facility, it may be advantageous to turn off the separate alarm system. This can be accomplished by placing a binary zero signal on the wire 78 to prevent the AND gate 70 from producing an alarm signal on the wire 72. It will be recognized by those of skill in the art that the override for the separate alarm may also be utilized in a similar manner to deactivate the normal entry and egress controls at each door protected by the access control system. Consequently, the whole system can be disabled, if such disabling should be desired, to permit personnel to pass through protected doorways without requiring each person to have his personnel identification card read by the card reader or requiring, on entry to restricted areas, that the individual enter his secret identification on the keyboard.

The foregoing description has described the operation and details of the door control 1. The details of the central control 3 of FIG. 1 are generally well known in the prior art. For exampale, the data storage 20 comprises two registers, one register for storing the keyboard data and the second register for storing card data. Electrical storage registers of the type used in electronic computers and the like are most advantageously utilized for the data storage 20. Since such registers are so well known in the prior art, a more detailed description is not herein provided.

The verification circuit 30 for the preferred embodiment of this invention is described in the above mentioned copending patent application and will not be described herein in any greater detail.

The Sequence Controller 18 in FIG. 1 comprises, in the preferred embodiment of this invention, a circuit like that shown in FIG. 2. The circuitry of FIG. 2 includes a free running clock which produces pulses at the binary one state on the clock output wire '101 at a periodic rate determined by the clock frequency which, for the preferred embodiment, has a frequency of approximately 600 kHz. The clock output 101 is connected to one of the inputs of an AND gate 102. So long as a nonactive signal is present on the input wire 103 to the AND gate 102, the output of the AND gate 102 on wire 104 will be unchanged and will not be operative to increment a counter 105 or to trigger a single shot timer 106.

The input wire 103 is connected to the output of the OR gate 107. Consequently, so long as all of the inputs to the OR gate 107 are not active, i.e. at their binary zero" state, the output thereof connected to wire 103 will remain non-active or at its binary zero state.

When the Sequence Controller 18 is started by the receipt of a start signal generated in a manner described earlier on the input line 108 to the OR gate 107, the input line 103 to AND gate 102 will become active i.e. at the binary one state. The input on the line 113 will also become active or at the binary one" state as described later in greater detail. Consequently, the first clock pulse with a binary one state received from the clock 100 over wire 101 will be transmitted through the AND gate 102 to a counter 105 to thereby increment the counter 105.

The counter 105 in the preferred embodiment of this invention comprises a counter having a single input for receiving and counting pulses and four output wires for providing a set of binary signals to thereby permit the counter 105 to provide binary outputs ranging from a value of to 15. The four binary output wires from the counter 105 are connected to a decoder 109 which has sixteen individual output wires, each output wire having a binary one signal thereon when a unique combination of input signals are applied thereto by the counter 105. As such, the Sequence Controller shown in FIG. 2 is operative to produce at the output of the decoder 109 sixteen different control signals for controlling the sequence of the system operation.

Each pulse on the output wire 104 which increments the counter 105, is operative to actuate a single shot timer 106. The single shot timer 106, in the preferred embodiment of this invention, comprises a timer which produces an active or binary one output signal after a period of twenty seconds has elapsed from the time that an input pulse was applied thereto. If such an active signal should be produced by the single shot timer 106, the active signal is connected to one input to the OR gate 107 to thereby produce an active signal on the input wire 103. Since the signal on the wire 113 is at its binary one state, as will become clear later, after a twenty second period of waiting with the counter 105 at a single value, the single shot timer 106 produces at its output a signal having a binary one value which is operative to permit the next clock pulse from the clock 100 to increment the counter 105. This subsequent clock pulse also restarts the single shot timer 106. In this manner, the Sequence Controller 18 can never remain in a condition with the counter 105 permanently set the one value other than to the value of one.

When the counter 105 reaches a value of zero, the

decoder 109 will produce an output signal having a binary one" state on the zero output line 110 which is connected to one input of the AND gate 111. The second input to this AND gate 111 is the inverse of the start signal. That is, a binary one signal is produced at the second input to the AND gate 111 when the start signal is not present on the start wire 108. The inverter 112 is operative to produce the inverse of the start signal at the input at the AND gate 111 which, in combination with the signal on the decoder output line 110 is operative to produce an output signal on line 113 to block the passage of clock pulses through the AND gate 102. Consequently, the counter 105 will remain at a value of zero until a subsequent start signal is received on the input line 108.

The counter 105 is incremented by the clock when certain synchronous operations are completed in the proper sequence. For example, when the decoder 109 produces an output on the line labeled n, an operation such as reading a card might be initiated. After the data from the card is read into the data storage within the central control 3, this card reading operation is completed. A signal from the data storage 20 to the Sequence Controller 18 over the line 114 (shown in FIG. 2) would indicate to the Sequence Control 18 that the card reading operation was complete. This active or binary one signal on the line 114 is applied to one input of a two input AND gate 115. The second input to this AND gate 115 is connected to the decoder output line n so that when the operation complete signal is placed on the input line 114, the AND gate 115 will provide an active or binary one signal to the OR circuit 107. The OR circuit 107 output will then be at a binary one state and this signal is wired to the input line 103 to the AND gate 102 to allow the next clock pulse from clock to increment the counter to the next sequence step. As such, the counter can be incremented by the proper conclusion of an operation by the system or by the single shot timer 106, the latter occurring only when the initiated operation is not completed within the time period of the single shot timer 106, which is 20 seconds for the preferred system.

Referring again to FIG. 1, the recorder 36 may comprise any suitable printing mechanism for recording data in readable form from various parts of the system. Specifically, the recorder 36 will provide a record of each event and this record preferably includes an event code which will identify the particular type of event which has occurred. In addition, the record includes the personnel identification number, if one is read from a personnel identification card, to thereby indicate the individual responsible for the recorded event. The record also includes an indication of the door at which the event occurred, the data on which the event occurred and the time at which the event occurred. All of this data is available from different elements of the central control 3..The recorder 36 may respond directly to the data, generated in different parts of the system, however, a print data register (not shown) is preferably provided for storing this information until used by the recorder 36.

The central control 3 additionally includes a day/- night switch or indicator 116 which provides a signal to the status check 34 which is utilized thereby to determine whether the individual is authorized to enter the restricted area at the time of day at which entry is attempted. The day/night switch 116 may be manually or automatically set to indicate whether the day or night access information contained on an individuals personnel identification card should be utilized in determining whether entry will be permitted. This operation will be described in greater detail below.

The central control 3 of FIG. 1 also includes a clock 117 as well as a date indicator 118 which are connected to the recorder 36. The clock 1 17 provides time signals to the recorder 36 so that the time of each system event can be recorded. The date indicator 118 also provides electrical data to the recorder 36 so that the data of each event is also recorded. The date indicator 118 may comprise a settable switch arrangement or may actually be a portion of the clock 117 which is utilized to produce this data indication.

Referring now to FIG. 3, the status check circuitry 34 is shown in greater detail along with other portions of the central control which interconnects therewith. As indicated generally above, the card data and the keyboard data are stored within a storage unit and, in FIG. 3, the keyboard data is stored in a register 20a and the card data is stored in a register b. The keyboard data is utilized only by the verification check circuit while the card data register 20b is utilized for the verification check as well as for other checks. The verification check itself is described in greater detail in the above identified copending patent application and will not be described in any greater detail here.

As indicated above, a printed record is prepared b the recorder 36 and the record includes many different pieces of information. One such piece of information included in the printed record is a door number to identify the door at which an event occurred. The print data register 200 provides a storage location for receiving all the data which is printed by the recorder 36 after the completion of each recording operation responsive to system events at one of the door control units. Digit positions 6 and 7 of the print data register 200 is reserved for receiving data which indicates the number of the door control unit at which the event occurred. This number data is placed into the print data register 200 by a decoder 202 which is activated whenever the Sequence Controller 18 produces a signal to cause a card reader at a particular door control unit to read the personnel identification card inserted therein. For instance, if the card reader at the door control 1 were to be actuated, the input wire labeled read card at door 1 would be actuated. This signal is applied to the decoder 202 to produce an output of 01 which is placed into the digit positions 6 and 7 of the data register 200. The read card at door 1 signal is also transmitted to the door control 1 and this signal is always activated for every controlled operation of the access control system of this invention, therefore, the proper door number is automatically placed into the print data register 200 by the decoder 202 for each recorded event. For convenience, the decoder 202 is drawn with six inputs, however, the preferred system is operable to control 16 doors. The additional circuitry necessary, though not shown, is essentially identical to the circuits already described.

As indicated generally above, a portion of the card data stored in register 200 and shown schematically as 204 comprises data corresponding to the system number for the particular access control system on which the original card data was encoded. Each attempt to enter a restricted area controlled by the access control system of this invention requires that the system number of the card data correspond identically to the system number of the access control system itself. If the system number for card data and the machine system number do not correspond, the access control system is operative to prevent the door from being unlocked and thereby prevents the individual from entering the restricted area. This blocking is accomplished through a circuit which includes a set of switches 206 which are manually settable to the system number assigned to the access control system. The system number data 204 from the card data register 20b and the switches 206 are connected to a compare circuit which produces a signal at its output on wire 208 which is active (binary one state) whenever the card data system number does not correspond to the system number as defined by the setting of the switches 206.

The active signal on wire 208 indicating that the system numbers do not compare is inverted by an inverter circuit 210 to produce an input to the AND gate 212 which will prevent the output of the AND gate 212 from becoming active. As will become more clear later, the output of the AND gate 212 is active whenever a normal entry occurs and all checks are successful. Consequently, the binary zero signal from the inverter 210 when the card data system number is not the same as the system number of the switches 206, is operative to prevent the indication of a normal entry.

The indication that the system number on the card and the system number according to the switches 206 are not the same as a binary one signal on wire 208 which is connected to one input of another AND gate 214. Assuming that the other input to this AND gate 214 is also active, the output of the AND gate 214 will provide an active input signal to the fourth input of an event decode circuit 216. The event decode circuit 216 is preferably a decoder which responds to a signal at one of eight inputs to produce a decimal code at its output which is stored in the print register 200 digit position 1. The code stored in the first digit position of the register 200 corresponds to the event code which identifies the type of system event which has occurred. While being indicated as a decoder for converting only eight individual event inputs into an output code, the decoder 216 may indeed be much larger in size to thereby identify even more events, should such identification be desirable. For the circuit shown, however, the event codes are identified below. some of these events will be described in even more detail later.

Code Meaning Normal entry Improper verification Attempt to enter area not authorized to enter Entry blocked Wrong system number Normal egress Other event Other event Another check briefly mentioned above which is performed by the status check circuitry 34 is the check to determine whether the individual is permitted to enter the particular restricted area that he seeks to enter. The entry control information, as indicated above, is stored on the personnel identification card itself and, for the preferred embodiment, comprises twelve data bits of information which, after the card is read, is stored in the card data register 20b as at 220 indicated generally. This information is divided into two six data bit fields, one field for daytime access data and the other field for nighttime access data. The day/night switch 116 is operative to control which six data bits are utilized at any given time to determine if the individual is permitted, according to the access control data on the individuals personnel identification card to enter the restricted area to which the individual seeks to enter. The day/night switch 116 is connected via a wire 222 to several AND gates shown generally as 224. When the signal on the wire 222 is active, one of the inputs to each of these AND gates 224 is active thereby permitting the possibility that one of these AND circuits may produce at its output an active signal indicating that the individual is authorized to pass through the particular door at which he has sought entry.

When the signal on wire 222 is active, the second six data bits of the access area data 220 are ignored because the inverter 226 inverts the signal on wire 222 to produce at its output a nonactive signal which is applied to a group of AND gates shown generally at 228 which prevent each such AND gate from producing an active output signal. These AND gates 228 are connected, as indicated, to the last six data bits of the access area data 220. As such, the day/night switch 116 is operative to consider either the first or second half of the access area data 220 at any one time.

Each of the AND gates 224 or 228 comprises a three input AND gate which produces an active signal at its output only when all three inputs are active. One input to each AND gate, as indicated above, comprises a signal representing whether it is day or night as controlled by the day/night switch 116. A second input is connected directly to one unique location in the access area data 220 stored in register 20b. The third input to each of these AND gate 224 of 228 corresponds to a signal from one particular door control unit so that only one such AND gate 224 or 228 can possibly produce an active output signal at any one time. Consequently, if an individual is seeking to enter at door number 1, an active signal will be produced on the wire 230 indicating this fact. Assuming the signal on wire 222 is active, if the wire 232, which connects between the input of the AND gate 234 and one data bit position of the access area data 220 is also active, all of the conditions at the input to the AND gate 234 have been met and, therefore, the output on wire 236 will also be active. This active signal is transmitted through the OR gate 238 .to provide an active signal which is applied to one input of the AND gate 212. As such, whenever the output of the OR gate 238 is active, this condition indicates that the individual seeking to enter the restricted area is authorized to enter the restricted area according to the data included on his personnel identification card.

Referring again to FIG. 3, blocking circuitry is provided to determine if an individual should or should not be permitted access to the restricted area controlled by the system. The blocking circuitry utilizes the personnel identification number 240 which comprises part of the card data which is stored in the card data register 20b. In the preferred embodiment of this invention, the identification number data 240 comprises twelve data bits of information which correspond to the personnel identification number assigned to the individual given a particular card. The high order data bits of the identification number are transmitted over wires 241 and the low order data bits of the identification number are transmitted over the wires 242 to form the address to a matrix 243. If the address to the matrix 243 on the wires 241 and 242 correspond identically to an identification number that has been blocked, that is, that the individual holding the card has been prohibited from entering any door controlled by the system, an active signal is produced at the output of the matrix 243 on the wire 244. This active signal on the wire 244 is transmitted through the inverter 245 to one of the four inputs to the AND gate 212. This active signal on the wire 244 is operative to prevent the AND gate 212 from producing an active signal at its output thus preventing unlocking of the restricted area door. The active signal on the wire 244 is also operative to produce an active output signal to the AND gate 246 provided the output of the OR gate 247 is also active. This latter condition will be true if the signal on wire 208 indicates that the system number of the card data is identical to the switch setting for switches 206 and that the signals on the wires labeled other event are not active. When the output of AND gate 246 is active, it will cause the event decoder 216 to produce an output signal having a decimal value of 3 for the event code which is stored in digit position 1 of the print data register 200. Whenever the event decoder 216 produces an event code of 3, it means that the individual who sought entry to a restricted area has been blocked from entermg.

in operation of the system, an individual may be blocked from entering for any number of reasons. One such reason is that the individual is no longer employed by the corporation having its doors protected by the access control system. Under these circumstances, should the personnel identification card remain in the possession of the individual, it is desirable to prevent such a former employee from entering the building. Also, as noted above, it may be useful to block groups of individuals ,from entering restricted areas. Such group blocking might be utilized under circumstances where union employees are on strike and the employer desires to prevent such union employees from entering the restricted areas while they are on strike.

To achieve this group blocking feature, the high order bits of the identification number 240 which are transmitted over the wires 241 are also sent to a decoder 250. This decoder 250 is settable and if the setting of the decoder 250 corresponds to the high order data bits of the identification number 240, an active signal is produced at the output 251 which will have the same effect as the active output from the matrix 243. As such, whenever the high order data bits of the personnel identification number 240 correspond to the setting of the decoder 250, the individual seeking entry into the restricted area belongs to a group of individuals who have been blocked from entering this restricted area and entry is prevented.

The circuitry for providing these blocking features is shown in greater detail in FIG. 4. The high order data bits of the identification number are indicated by the four lines labeled lD0, lDl, lD2, and ID3. These four high order data bit lines are connected to the input of a decoder circuit 252 which will produce an active signal at one of sixteen output lines.

Each output line from the decoder 252 is connected to another decoder and is operative to activate the connected second decoder. By way of example, the output from decoder 252 labeled 15 which becomes active whenever the binary value for the four high order data bits of the personnel identification number are all one, is connected to one input of decoder 253 and 260 to thereby activate then decoders 253 and to decode the remaining data bits of the personnel identification number. The decoder 253 operates in the same manner as decoder 252 and produces at its output one active line out of sixteen which corresponds to the binary value for the four data bits ID4-ID7.

Each output of the decoder 252 is also connected to a unique block group switch which is selectively utilized to pass the active signal from the decoder 252 to the output of the decode circuitry to thereby produce a block entry signal for any individual whose identification number contains a specific high order bit combination. By way of example, the 15 output of decoder 252 is connected to a block group switch 254. Whenever the output 15 of the decoder 252 is active and whenever the block group switch 254 is closed, an active signal from the decoder 252 on the output will be transmitted to the input of an OR gate 255 to thereby produce an active signal at the output thereof which is labeled block entry. This block entry signal corresponds to the active signal described in connection with wire 244 shown in FIG. 3 and is operative, for the example selected, to prevent any person with a per sonnel identification number with ones in the first four bit positions thereof from entering the restricted area.

Other block group switches are provided and these are connected to other outputs of the decoder 252 to thereby permit decoding of any one of the sixteen outputs of the decoder 252 to block entry to a restricted area of individuals having selected high order bit combinations in their personnel identification number. It will be recognized by those skilled in the art that the group blocking switches, such as switch 254, may be operative in response to decoding of any other group of data bits in a personnel identification number and need not be restricted to decoding sequential or only the high order bit positions.

In addition to the group blocking circuitry shown in FIG. 4, selective blocking circuitry is also shown to selectively block individuals from entering restricted areas. This circuitry allows selected individuals to be excluded from entering the restricted area. To achieve this objective, the output of the decoder 252 as indicated above, produces an active signal on one of sixteen different wires which are each connected to a second decoder like decoder 253 which each have four input wires connected to bits ID4-ID7 of the personnel identification number. Each such decoder 253 has sixteen output terminals each of which is connected to one horizontal wire on a matrix board 256. As such, when a signal appears on one of the horizontal wires of the matrix 256, the first eight data bits of the personnel identification number have been decoded.

As shown in FIG. 4, the matrix board 256 has sixteen horizontal wires as well as 16 vertical wires. There is no actual intersection between these wires, however, a connecting pin such as a diode pin can be inserted at the intersection point between any of the horizontal wires with any of the vertical wires. As a consequence,

an active signal may be transmitted from any horizontal wire to any vertical wire if a diode pin is inserted at the intersection. When an individual is blocked from entering the restricted area, the system owner merely has to locate on one of sixteen matrix boards like that for matrix 256 and inset a pin in the hole which corresponds to the identification number of the individual who is blocked. For example, a diode pin might be inserted at a point shown generally at 257. This would correspond to an individual who has an identification number represented in binary as follows: I l 1 1000010. As such, if the diode pin 257 were inserted in the matrix board 256 and if the decoder 253 produced an output on the zero output wire, an active signal would be transmitted from the zero output wire through the diode 257 to the vertical wire labeled 2 for the matrix board 256. It should also be noted that more than one of the sixteen intersection points on each horizontal wire may have a diode pin inserted therein. For example, a diode pin 258 might be inserted as shown and this would correspond to an individual having a personnel identification number: 11110001111.

Each of the vertical wires in the matrix board 256 is connected to a unique AND gate shown generally at 259. Each of these AND gates have a second input which is connected to a unique output of a decoder circuit 260 which decodes the low order personnel identification number data bits ID8, [D9, ID10, and lDll. If any one of the AND gates 259 have two active input wires, an active signal is produced at its output to thereby cause an active signal to be produced at the output of the OR gate 255 to thereby block entry to the restricted area for the individual seeking to enter this area. Consequently, should one of the vertical wires from a matrix board 256 be active and the corresponding output of the decoder 260 connected to the same AND gate 259 also be active, the individual will be blocked from entering the restricted area because an active signal will appear at the output of the OR gate 255 which is operative in a manner described above to block entry to the restricted area.

Returning again to FIG. 3, circuitry is provided within the dotted line 270 to provide for the event decoder 216 in the event that more than one condition is present which should block entry of the individual to the restricted area. For example, the individual might be seeking to enter the restricted area with a card for another system and the individual also might fail to insert the proper secret number corresponding to his personnel identification number. As such, a wrong system number indication would appear on the wire 208 and also a no verification indication would be placed on the wire 32. Assuming that the output of the OR gate 271 is active, the AND gate 214 will produce an active signal at its output. At the same time, however, an active signal is applied to the wire 272 which is one of the inputs to the AND gate 273. In order to prevent a second input from being applied to the input of the event decoder 216, the signal on the input wire 274 of the AND gate 273 must not be made active. This, in fact, occurs because the active signal on the wire 208 is inverted by an inverter circuit 275 to produce a nonactive signal at its output. This nonactive signal is applied to the input of the OR gate 276. This will produce a nonactive signal at the output of the OR gate 276 on a wire 274 connected to one input to an AND gate 273 thereby preventing an active signal from appearing at the output of the AND gate 273.

Other similar circuitry is provided within the dotted line 270 to provide a priority for the specific event which may be decoded by the event decoder 216 should more than one event occur. According to the priority scheme established by this circuitry, the event decoder 216 is operative to produce signals representing events having a coding in the order ranging from 7 to 0 with the higher decimal values of the event code having priority over lower decimal values for the event code.

In the event that all of the tests performed by the status check circuitry are passed successfully, the AND gate 212 will produce an active signal at its output 280 which forms the zero input to the event decoder 216. Since no other event can occur simultaneously with an active signal on the Wire 280, this wire is connected directly to the zero input of the event decoder 216 to thereby produce a zero event code to indicate that a normal entry has occured at a door. This signal is also utilized as an input to one of the AND gates shown generally at 281. This signal in combination with one of the Entry Ready signals is operative to produce an active signal at the output of one of these AND gates 281. These output signals are connected directly to the door control unit at the door corresponding to the location where entry is being sought. This signal comprises an unlock door signal which is operative to unlock the door at the door control to thereby permit the individual to enter the restricted area.

In the situation where a normal egress has occured, the normal egress wire in FIG. 3 will be actuated by the receipt at the status check 34 of an indication that an egress at any door has occured. Such a signal is generated for door 1, for example, at the wire 62 shown in FIG. 1. This egress signal comprises one input to an AND gate 277. The second input to this AND gate 277 is active whenever the system generates a read card signal to read the personnel identification card at the door control. When both of the inputs to the AND gate 277 are active, the output thereof will be active. This active output signal from the AND gate 277 is connected by a wire 278 to the five input of the event decoder circuit 216 which produces a 5 at its output for insertion into digit position 1 of the data register 200.

While the foregoing description of the invention has been made with particular emphasis on a preferred embodiment therefor, numerous modifications may be made to this system without departing from the spirit and scope of the invention. For example, in order to simplify the system description, the system has been described as having six different doors. The preferred system has, however, sixteen doors. It will be recognized by those of skill in the art that many more doors may be utilized by this system, however, additional circuitry must be provided and this additional circuitry would be connected in parallel with existing circuits to thereby produce identical operations at additional doors.

In addition to adding more doors to the system, it is possible to add additional status checks to the system should such additional checks be desirable. Indeed, circuitry is provided for handling two additional other events in the priority circuitry 270 although the nature of these other events has not been specifically defined. Further, while the described attempt counter is operative after seven attempts at entry to erase the personnel identification card, clearly other settings for the attempt counter might be selected.

The preferred system described above includes a day/night switch used in connection with testing the access area data from the personnel identification card. In an alternative system, the day/night switch can be replaced by a three position switch so that the access controller of this invention can be used at facilities having three work shifts a day. With such an option, additional access area information may be desirable so the card data field must be expanded accordingly. A further alternative is to use the day/night switch as a weekday/weekend switch for controlling access in one manner on weekdays and in another manner on weekends. Furthermore, each of the above described alternative approaches may be combined with another such approach to thereby produce a system with expanded capability.

These and other modifications in form only may be made readily by those of skill in the art without departing from the spirit and scope of this invention as defined by the following claims.

What is claimed is:

1. An accesscontrol system for controlling movement into and out of a restricted area through a door by personnel having an identification card; the system comprising, in combination;

a remotely controllable e s .7 hanism for selectively permitting the door to the restricted area to be opened in response to door unlock signals, said door lock mechanism being normally locked,

a personnel detector within the restricted area to detect a person within said restricted area adjacent said door and in response thereto to generate a personnel signal,

a door sensor for producing a door open signal when the door to the restricted area is open;

an egress detector responsive to the occurrence of said door open signal and personnel signal to produce an egress signal;

a personnel identification card reader located outside the restricted area for reading card data from a personnel identification number;

a central control responsive to said egress signal to provide a read signal to said card reader;

a recorder;

said central control including means operative to receive the personnel identification number from said card reader and to actuate said recorder to record that an egress has occurred and the personnel identification number from the card read by said card reader; and

said central control including further means operative to produce a door unlock signal to unlock said door in response to specified conditions including reading of a card inserted in said reader by a person outside said restricted area seeking entry who inserts a personnel identification card in said reader when the door is locked.

2. The access control system of claim 1 additionally including:

means associated with said card reader for producing a card absence signal when no card is in said reader, means for producing a humanly perceptible signal in response to coincidence of a said card absence signal and said egress signal, said humanly perceptible signal reminding personnel leaving the restricted area to insert their personnel identification card into said card reader.

3. The access control system of claim 2 wherein:

said central control is operative after a predetermined period of time to turn off said egress signal causing said humanly perceptible signal to be generated only for a predetermined time period in the absence of card insertion.

4. The access control system of claim 3 wherein:

said central control includes means to actuate said recorder to indicate that an egress has occurred and that no personnel identification card had been read upon expiration of said predetermined time period without card insertion.

5. The access control system of claim 1 additionally including:

a keyboard located near said card reader outside the restricted area, said keyboard being provided for entering, by personnel seeking to enter the restricted area, a secret number which corresponds to the personnel identification number on their personnel identification card;

6. The access control system of claim wherein:

, said central control is operative to activate said recorder when the secret number and personnel identification number correspond to indicate that a normal entry has occurred and also to record the personnel identification number from the card read by said card reader, thereby providing an access control system with a means for providing a record of all movement of personnel through a doorway of a restricted area.

7. The access control system of claim 5 wherein:

said central control includes a blocking circuit responsive to said read personnel identification number for determining if said read personnel identification number corresponds to a person who has been blocked from entering the restricted area, said blocking circuit including recorded manifestations of blocked personnel for producing a block signal if said read personnel identification number corresponds to a person blocked, said blocking signal being operative to inhibit generation of said door unlock signal to prevent unlocking said door lock mechanism.

8. The access control system of claim 7 wherein;

said blocking circuit includes a plurality of interrupted connections, each associated with one personnel identification number, each interrupted connection being selectively rendered continuous by a connector means, said blocking signal being generated when the personnel identification number of the card read by said card reader corresponds, identically to an interrupted connection rendered continuous by a connector means.

9. The access control system of claim 7 wherein:

said blocking circuit includes a group block circuit for blocking groups of personnel from entering the restricted area, said group blocking circuit responding to selected portions of said read personnel identification number to produce said block signal when the selected portions of said personnel identification number corresponds to a group who have been blocked.

10. The access control system of claim 9 wherein:

said blocking circuit includes a plurality of interrupted connections, each associated with one personnel identification number, each interrupted connection being selectively rendered continuous by a connector means, said blocking signal being generated when the personnel identification number of the card read by said card reader corresponds identically to an interrupted connection rendered continuous by a connector means.

11. The access control system of claim 5 wherein:

said blocking circuit includes a group block circuit for blocking groups of personnel from entering the restricted area, said group blocking circuit responding to selected portions of said read personnel identification number to produce said block signal when the selected portions of said personnel identification number corresponds to a group who have been blocked.

12. The access control system of claim 11 wherein:

said blocking circuit includes a plurality of interrupted connections, each associated with one personnel identification number, each interrupted connection being selectively rendered continuous by a connector means, said blocking signal being generated when the personnel identification number of the card read by said card reader corresponds identically to an interrupted connection rendered continuous by a connector means.

13. The access control system of claim 5 wherein:

said card includes access area data recorded thereon, said access area data being correlated to restricted areas to which personnel can be selectively admitted;

an indicator means having at least two output signals correlated to at least two different time periods;

said central control includes an access area control circuit responsive to said access area data and said indicator means, said access area control circuit being operative to inhibit generation of said unlock signal to prevent unlocking of said door lock mechanism if the access area data read the personnel identification card does not include data indicating that the individual is permitted to enter the restricted area to which entry is sought at the time of day indicated by said indicator means.

14. The access control system of claim 5 additionally including:

an entry attempt counter responsive to reading of said keyboard entered data, said entry attempt counter being incremented each time said keyboard receives a complete secret number entered therein, said entry attempt counter producing an erase card signal when said counter reaches a predetermined value, said erase signal being input to said card reader, said card reader including circuitry responsive to said erase signal to erase the card data on the card inserted therein, thereby preventing further use of the personnel identification card to enter the restricted area, said counter being reset without production of said erase signal in response to said unlock signal.

15. The access control system of claim 1 wherein:

said card data of each said personnel identification card includes a multidigit number in machine readable form coded thereon, said number including a multi-digit personnel identification number; and

said central control further responsive to said card reader for receiving the personnel identification number read by said card reader, said central control including a settable decoder responsive to selected digits of the read personnel identification number, said decoder producing a block signal when the selected digits of the read personnel identification number corresponds identically to the preset setting for said decoder, said block signal being operative to prevent the generation of unlock signals, thereby preventing an individual who belongs to a group of individuals blocked from entering the restricted area from entering the restricted area. z

16. The access control system of claim 1 wherein:

said card data of each said personnel identification card includes a multi-digit number in machine readabie-fomcodeithersgm said number including a multi-digit personnel identification number; and

said central control further responsive to said card reader for receiving the personnel identification number read by said card reader, said central control including a settable decoder responsive to selected digits of the read personnel identification number, said decoder producing a block signal when the selected digits of the read personnel idensaid blocking circuit includes a group block circuit for blocking groups of personnel from entering the restricted area, said group blocking circuit responding to selected portions of said read personnel identification number to produce said block signal when the selected portions of said personnel identification number corresponds to a group who have been blocked.

PATENT NO.

DATED INVENTORtS) i It is certified that error appears in the above identified patent and that said Letters Patent are hereby corrected as shown below;

.Column [SEAL] UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION 3,866,173 February 11, 1975 Charles J. Moorman et a1 line 43, change the" to -to-.

line 4, change "control" to --controller.

line 58, change "data" (second instance) to 5tate--- line 62, change "data" to -date.

line 17, change of"' second occurrence to 01" line 54, change "160" to 260-.

line 51, change "inset" to --insert--.

Signed and Sealed this twenty-sixth Day Of August 1975 Arrest:

RUTH C. MASON Arresting Officer C. MARSHALL DANN ('mnrrlissiumr ofParenrs and Trademarkx 

1. An access control system for controlling movement into and out of a restricted area through a door by personnel having an identification card; the system comprising, in combination; a remotely controllable door lock mechanism for selectively permitting the door to the restricted area to be opened in response to door unlock signals, said door lock mechanism being normally locked, a personnel detector within the restricted area to detect a person within said restricted area adjacent said door and in response thereto to generate a personnel signal, a door sensor for producing a door open signal when the door to the restricted area is open; an egress detector responsive to the occurrence of said door open signal and personnel signal to produce an egress signal; a personnel identification card reader located outside the restricted area for reading card data from a personnel identification number; a central control responsive to said egress signal to provide a read signal to said card reader; a recorder; said central control including means operative to receive the personnel identification number from said card reader and to actuate said recorder to record that an egress has occurred and the personnel identification number from the card read by said card reader; and said central control including further means operative to produce a door unlock signal to unlock said door in response to specified conditions including reading of a card inserted in said reader by a person outside said restricted area seeking entry who inserts a personnel identification card in said reader when the door is locked.
 2. The access control system of claim 1 additionally including: means associated with said card reader for producing a card absence signal when no card is in said reader, means for producing a humanly perceptible signal in response to coincidence of a said card absence signal and said egress signal, said humanly perceptible signal reminding personnel leaving the restricted area to insert their personnel identification card into said card reader.
 3. The access control system of claim 2 wherein: said central control is operative after a predetermined period of time to turn off said egress signal causing said humanly perceptible signal to be generated only for a predetermined time period in the absence of card insertion.
 4. The access control system of claim 3 wherein: said central control includes means to actuate said recorder to indicate that an egress has occurred and that no personnel identification card had been read upon expiration of said predetermined time period without card insertion.
 5. The access control system of claim 1 additionally including: a keyboard located near said card reader outside the restricted area, said keyboard being provided for entering, by personnel seeking to enter the restricted area, a secret number which corresponds to the personnel identification number on their personnel identification card; said central control being responsive to entry of said secret number on said keyboard to transfer said keyboard entered number to said central contrOl and also to read the personnel identification card in said card reader; said central control including a verification circuit to verify that the secret number corresponds to the personnel identification number read from the personnel identification card, said central control producing a door unlock signal if said verification circuit determines that the secret number and the personnel identification number properly correspond to each other.
 6. The access control system of claim 5 wherein: said central control is operative to activate said recorder when the secret number and personnel identification number correspond to indicate that a normal entry has occurred and also to record the personnel identification number from the card read by said card reader, thereby providing an access control system with a means for providing a record of all movement of personnel through a doorway of a restricted area.
 7. The access control system of claim 5 wherein: said central control includes a blocking circuit responsive to said read personnel identification number for determining if said read personnel identification number corresponds to a person who has been blocked from entering the restricted area, said blocking circuit including recorded manifestations of blocked personnel for producing a block signal if said read personnel identification number corresponds to a person blocked, said blocking signal being operative to inhibit generation of said door unlock signal to prevent unlocking said door lock mechanism.
 8. The access control system of claim 7 wherein: said blocking circuit includes a plurality of interrupted connections, each associated with one personnel identification number, each interrupted connection being selectively rendered continuous by a connector means, said blocking signal being generated when the personnel identification number of the card read by said card reader corresponds identically to an interrupted connection rendered continuous by a connector means.
 9. The access control system of claim 7 wherein: said blocking circuit includes a group block circuit for blocking groups of personnel from entering the restricted area, said group blocking circuit responding to selected portions of said read personnel identification number to produce said block signal when the selected portions of said personnel identification number corresponds to a group who have been blocked.
 10. The access control system of claim 9 wherein: said blocking circuit includes a plurality of interrupted connections, each associated with one personnel identification number, each interrupted connection being selectively rendered continuous by a connector means, said blocking signal being generated when the personnel identification number of the card read by said card reader corresponds identically to an interrupted connection rendered continuous by a connector means.
 11. The access control system of claim 5 wherein: said blocking circuit includes a group block circuit for blocking groups of personnel from entering the restricted area, said group blocking circuit responding to selected portions of said read personnel identification number to produce said block signal when the selected portions of said personnel identification number corresponds to a group who have been blocked.
 12. The access control system of claim 11 wherein: said blocking circuit includes a plurality of interrupted connections, each associated with one personnel identification number, each interrupted connection being selectively rendered continuous by a connector means, said blocking signal being generated when the personnel identification number of the card read by said card reader corresponds identically to an interrupted connection rendered continuous by a connector means.
 13. The access control system of claim 5 wherein: said card includes access area data recorded thereon, said access area data being correlated to restricted areas to which personnel can bE selectively admitted; an indicator means having at least two output signals correlated to at least two different time periods; said central control includes an access area control circuit responsive to said access area data and said indicator means, said access area control circuit being operative to inhibit generation of said unlock signal to prevent unlocking of said door lock mechanism if the access area data read the personnel identification card does not include data indicating that the individual is permitted to enter the restricted area to which entry is sought at the time of day indicated by said indicator means.
 14. The access control system of claim 5 additionally including: an entry attempt counter responsive to reading of said keyboard entered data, said entry attempt counter being incremented each time said keyboard receives a complete secret number entered therein, said entry attempt counter producing an erase card signal when said counter reaches a predetermined value, said erase signal being input to said card reader, said card reader including circuitry responsive to said erase signal to erase the card data on the card inserted therein, thereby preventing further use of the personnel identification card to enter the restricted area, said counter being reset without production of said erase signal in response to said unlock signal.
 15. The access control system of claim 1 wherein: said card data of each said personnel identification card includes a multi-digit number in machine readable form coded thereon, said number including a multi-digit personnel identification number; and said central control further responsive to said card reader for receiving the personnel identification number read by said card reader, said central control including a settable decoder responsive to selected digits of the read personnel identification number, said decoder producing a block signal when the selected digits of the read personnel identification number corresponds identically to the preset setting for said decoder, said block signal being operative to prevent the generation of unlock signals, thereby preventing an individual who belongs to a group of individuals blocked from entering the restricted area from entering the restricted area.
 16. The access control system of claim 1 wherein: said card data of each said personnel identification card includes a multi-digit number in machine readable form coded thereon, said number including a multi-digit personnel identification number; and said central control further responsive to said card reader for receiving the personnel identification number read by said card reader, said central control including a settable decoder responsive to selected digits of the read personnel identification number, said decoder producing a block signal when the selected digits of the read personnel identification number corresponds identically to the preset setting for said decoder, said block signal being operative to prevent the generation of unlock signals, thereby preventing an individual who belongs to a group of individuals blocked from entering the restricted area from entering the restricted area.
 17. The access control system of claim 16 wherein: said blocking circuit includes a group block circuit for blocking groups of personnel from entering the restricted area, said group blocking circuit responding to selected portions of said read personnel identification number to produce said block signal when the selected portions of said personnel identification number corresponds to a group who have been blocked. 